1. Field of the Invention
The invention is in the field of mechanical refrigeration and more particularly relates to refrigeration compressors having an oil sump. The invention further relates to means for providing a reservoir external to the compressor when the refrigeration system is of the sort that the amount of oil it holds in circulation is a variable, so that at one time a great deal of oil might be in circulation and at another time only a small amount of oil would be in circulation.
The invention further relates to the application of a pump to withdraw oil from the reservoir and deliver it in excess quantity to the compressor sump and further relates to the application of an overspill conduit from the compressor pump back to the oil reservoir so that the unneeded excess of oil delivered to the compressor sump by the pump will simply flow by gravity back into the reservoir.
The invention further relates to the use of a high side or a low side separator to remove oil from the flowing refrigerant and to return it directly or indirectly to the oil reservoir.
2. Description of the Prior Art
There is available an oil return system at present manufactured by the AC&R Company and by the Sporlan Valve Company which utilizes a high side oil separator installed in the compressor discharge line. The separated oil is delivered to a storage reservoir which is maintained at a pressure about 15 psi above suction pressure by a pressure differential regulating valve. The flow of oil to the compressor is adjusted by a float mounted on the side of the compressor. The float senses the level of the oil within the compressor sump. When the oil level is higher than the float setting, the float closes the oil supply valve and no flow from the oil reservoir to the sump can occur. When the oil level in the compressor sump is lower than the float setting, the valve, governed by the position of the float, opens, and the oil flows into the compressor sump from the pressurized oil reservoir.